In various wired and wireless communication systems the performance of a receiver is degraded by interfering signals originating from a transmitter. Methods for suppressing such interference are known in the art. For example, International PCT Publication Application WO2004/114578 describes an echo cancellation (EC) system for use in an ADSL System (312). The EC system includes an EC unit that generates a digital echo estimate signal at a lower sampling rate of the transmitted signal and then interpolates the digital signal to a higher sampling rate to cancel an echo signal thereby reducing complexity (304). The digital interpolated echo estimate signal is converted to analog form for use in analog echo cancellation (306). A subtracted signal resulting from the analog echo cancellation is converted into digital domain and used as feedback for the EC unit to adaptively improve the accuracy of the echo estimate (308).
U.S. Patent Application Publication 2018/0287659 describes systems and methods for full duplex DOCSIS cable modem echo cancellation with training. During reception of downstream signals, echo effects on downstream signals may be determined, with at least some of the echo effects corresponding to concurrently transmitted upstream signals. Echo cancellation corrections may be determined based on the determined echo effects, and the echo cancellation corrections may be applied during processing of the downstream signals. The echo cancellation may include or be based on preforming echo cancellation training, during active communication and based on one or both of the downstream signals and the upstream signals.
An international telecommunications standard, referred to as “Data Over Cable Service Interface Specification” (DOCSIS) that was developed by CableLabs and contributing companies, specifies the transfer of high-bandwidth data over existing cable TV (CATV) systems. In 2017, a Full Duplex (FDX) version of DOCSIS version 3.1 has been announced, in which at least part of the spectrum of the cable plant can be used simultaneously in both upstream and downstream directions. The physical layer of the DOCSIS 3.1 standard, including FDX, is specified, for example, in Annex F of the specifications “Data-Over-Cable Service Interface Specifications DOCSIS® 3.1, Physical Layer Specification,” CM-SP-PHYv3.1-I16-190121, January 2019.